Balloon altitude control device



June 18, 1963 C. P. FAZIO ETAL BALLOON ALTITUDE CONTROL DEVICE Filed Jan. 3,. 1961 1/111, III/IA carrying unmanned balloon at a constant altitude.

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'sive to atmospheric pressure increases.

United States PatentO 3,094,246 BALLOON ALTITUDE CONTROL DEVICE Charles P. Fazio, Hull, David G. Greenlie, Weston, Robert M. Nelson, Arlington, and Beverly A. Nickerson, Concord, Mass., assignors to W. R. Grace & Co., Cambridge, Mass., a corporation of Connecticut Filed Jan. 3, 1961, Ser. No. 80,230

4 Claims. (Cl. 222-52) This invention relates to an apparatus and method for controlling the altitude of a balloon. More particularly, this invention is concerned with a ballast releasing balloon altitude control device responsive to atmospheric pressure.

Quite often it is desired to maintain an instrument- The altitude of a balloon tends to vary during its flight because of changes in its lifting capacity, for example, from the loss of lifting gas or from changes in the volume of the lifting gas. The volume of lifting gas decreases when it 'cools after the sun sets. This is known as the sunset effect. This loss of lifting capacity can be compensated for by using devices which attach to the balloon and operate to increase or decrease the gross lift of the balloon as by adding or releasing lifting gas or by releasing ballast.

A device used to control the altitude of a balloon is desirably a light automatic mechanical device of simple construction. It should be reliable and reasonably sensi- A balloon altitude control device customarily receives rough handling during the launching of the balloon. Also, they are quite often used only once, i.e. they are lost with the balloon. Those devices which are of foolproof simplicity, inexpensive, and rugged are prized.

The balloon altitude control device of the present invention meets these criteria. It controls the gross lift of the balloon and thus its altitude by jettisoning ballast respon- This device has a simple reliable mechanical design which is automatic in nature and inexpensive. Its control action is such that it does not release ballast during ascent of the balloon, but becomes operative when the balloon has reached the desired altitude and starts to descend.

The device of the present invention will become clear from the following description of the drawings attached to and forming a part of this specification. FIGURE 1 is an elevational view in section of the ballast releasing device showing the device When it is ascending. FIG- URE 2 is a similar elevational view showing the device when it is descending and releasing ballast. FIGURE 3 is a view showing a typical uni-directional valve stemlock which is utilized as element in this invention. Like parts in the drawings have the same numbers.

In general, the device of this invention consists of a hollow container 11, which serves as a reservoir for ballast 12. The upper end of the container is provided with one or more openings :14 for loading the ballast. The lower end of the container is provided with an opening or port 16 which serves as a discharge port for the ballast. The drawings illustrate container 11 as having a two piece construction, with cap 15 which contains port 16 being attached to the lower end portion of the container :11. A one piece structure can, of course, be used. The ballast can be a liquid such as kerosene which does not freeze at the low temperature encountered at high altitudes, or it can be a suitable particulate solid such as ironfilings or bird-shot.

A plug or sealing means 18 fits within port 16 forming a valve. The valve is designed in this case to control the flow of liquids. Other valve designs and container arrangements can be used to regulate the release of the ballast, e.g., if a particulate ballast is used the bottom "ice portion of container 11 can be conical and be stoppered with a complementary conical plug or a horizontally movable slide.

A pressure responsive element 23 is connected to plug 18 by means of a uni-directionally telescoping or collapsing member. The pressure responsive element illustrated is an aneroid bellows which externally communicates with the atmosphere. The pressure-responsive element exerts a pushing force with decreases in atmospheric pressure, and a retracting or pulling force with increases in atmospheric pressure. Bourdon tubes, such as those of the helical or spiral type, can also be used as the pres- .sure responsive element as well as a simple, small encased balloon.

The pressure responsive element is shown as being located within container 11. It can also be located above or beside the container or below port 16.

The connecting unidirectionally telescoping member illustrated comprises a rod 22 attached to the pressure responsive element 23, a hollow tube 19 which is attached to plug 18 and receives rod 22, and a uni-directional valve stem-lock 21 attached to the top of tube 19. The valve stem-lock is more fully illustrated in FIGURE 3. It comprises a simple metal shape like the spring clips used to attach trim to automobiles. It has a center opening to receive rod 22 and two downwardly inclined locking tabs 32 in the center opening, only one of which is shown. The tabs 32 resiliently engage rod 22 and permit the rod to slide downwardly through the opening, but pinch and hold it when the rod attempts to move upwardly. Equivalent friction or slip-lock designs can be used if desired.

The telescoping member can have other constructions, e.g. a ratchet arrangement can be formed by threading the inside of tube 19 and placing an upwardly opening V-spring on the bottom of rod 22, with the V-spring engaging the threads of the tube. This permits the requisite telescoping of the connecting member but does not perthe container. The mechanical action of the bellows can be magnified or increased by suitable means, e.g., in the arrangement shown, bellows 23 can connect to the short end of .a pivot linkage, with the longer end of the pivot linkage connecting to rod 22.

The whole of the device including the bellows can be made of a plastic such as polyethylene or a phenolformaldehyde, or certain parts can be made of a plastic and others of metal. For example, elements 23, 22, and 21 and 19 can be made of metal and the remainder can be made of molded polyethylene. Absolute accuracy of the pressure responsive element is not necessary because the altitude control device is self-adjusting. Thus, an expensive bellows construction is not needed. Suitable load loops or attaching means are placed on container 11 to permit the device to be attached to the balloon.

As an example, the device may be sized to hold about 800 grams of kerosene and be used to control the flight of a 20-foot diameter balloon designed to reach an altitude of 100,000 feet. The kerosene is placed into container 11 through openings -14 with plug 18 being seated in port 16 at the time. When the balloon is relased and the ballast release device is carried aloft, the atmospheric pressure decreases and bellows 23 expands pushing rod 22 into shaft 19 and maintaining port 16 closed. This action is largely unrestrained and the overall length of the telescoping member becomes smaller. This diminishing in the length of the telescoping member continues until the desired altitude is reached and the balloon levels oif. The altitude that the balloon reaches may be controlled by the proper sizing of the envelope and/or by providing means for the release of the excess lift gas when the desired altitude is reached.

When the balloon starts to descend, for example, because of the sunset effect, the aneroid bellows contracts because the descent results in an increase in atmospheric pressure. This contraction exerts a vertical pull on rod 22. The valve stem-lock 21 prevents the two pieces of the telescoping member from moving apart and as a consequence, plug 18 is lifted from port 16 and some of the liquid ballast is released. The amount that bellows 23 contracts depends on the degree of change in the ambient atmospheric pressure. Thus, if the balloon has descended only a small amount, plug 18 will only be lifted a small amount from port 16, and the rate of liquid release will be relatively low. If a large descent has occurred, bellows 23 will contract to a greater extent and port 16 will be opened farther permitting more rapid release of the ballast.

The release of ballast increases the gross lift of the balloon and the balloon ascends. In ascending the atmospheric pressure decreases and bellows 23 expands. This forces plug 18 to close port 16 and stops the release of ballast. If the balloon again star-ts to descend, bellows 23 will contract and port 16 will again be opened to permit the discharge of additional ballast.

Having described this invention, what is sought to be protected by Letters Patent is succinctly set forth in the following claims.

What is claimed is:

1. A ballast release device for attachment to a balloon comprising, in combination: a container adapted to hold fluid ballast; openable and closeable ballast discharge means in the lower portion of said container; a pressure responsive element which contracts with increases in atmospheric pressure and expands with decreases in a-trnospheric pressure; and a uni-directionally collapsing shaft having one end connected to said ballast discharge means and the other end connected to said pressure responsive element, said shaft being operative to open said discharge means when said pressure responsive element contracts and to close said discharge means when said pressure responsive element expands to give intermittent opening and closing of said discharge means as the balloon descends and ascends. I

2. A ballast release device for attachment to a balloon comprising, in combination: a container adapted to contain fluid ballast; openable and closable ballast discharge means in the lower portion of said container; an aneroid bellows operatively housed within the upper portion of said container which contracts with increases in atmospheric pressure and expands with decreases in atmospheric pressure; a hollow tube connected to said ballast discharge means; a valve-stem the upper end of which is connected to said aneroid bellows and the lower end of which fits within said hollow tube; and means at the junction of said hollow tube and said valve-stem preventing the extraction of said valve-stem from said tube but permitting telescoping thereof, said tube being operative to opensaid discharge means when said bellows contracts and to close said discharge means when said bellows expands to give intermittent opening and closing of said discharge means as the balloon descends and ascends.

3. A ballast releasing altitude control device responsive to changes in atmospheric pressure comprising in combination: a container adapted to contain fluid ballast; openable and closable ballast release means in the lower portion of said container; a pressure responsive element communicating with the atmosphere and adapted to exert a pushing force with decreases in atmospheric pressure and a retracting force with increases in atmospheric pressure; and a uni-directionally telescoping connecting member attached to said pressure responsive element and to said ballast release means which member is operative to contract with said pushing force and thereby close said ballast release means and to be inextensible with said retracting force and thereby open said ballast release means whereby said fluid ballast is intermittently released with increases in atmospheric pressure.

4. The device of claim 3 wherein said ballast release means is a ball valve, and wherein said connecting member comprises a hollow shaft attached to said ball valve, a rod within said shaft member and attached to said pressure responsive element and an uni-directional locking means between said hollow shaft and said rod, preventing extraction of said rod from said shaft member.

References Cited in the file of this patent UNITED STATES PATENTS 2,652,175 Davis Sept. 15, 1953 2,904,285 Huch Sept. 15, 1959 2,924,408 Yost Feb. 9, 1960 

1. A BALLAST RELEASE DEVICE FOR ATTACHEMENT TO A BALLOON COMPRISING, IN COMBINATION: A CONTAINER ADAPTED TO HOLD FULID BALLAST; OPENABLE AND CLOSEABLE BALLAST DISCHARGE MEANS IN THE LOWER PORTION OF SAID CONTAINER; A PRESSURE RESPONSIVE ELEMENT WHICH CONTRACTS WITH INCREASES IN ATMOSPHERIC PRESSURE AND EXPANDS WITH DECREASES IN ATMOSPHERIC PRESSURE; AND A UNI-DIRECTIONALLY COLLAPSING SHAFT HAVING ONE END CONNECTED TO SAID BALLAST DISCHARGE MEANS 